Bates said city investigators did not yet know the cause of the collapse. “This is a wake up call and we don’t want this thing to happen again,” he said.

The city of Berkeley said it had ordered the property owner to immediately remove the collapsed balcony and to perform a structural assessment of the remaining balconies within 48 hours.

Police chief Michael Meehan said he doubted criminal charges would come about from the incident. “We don’t have any indication of criminal activity,” he said, adding that “local police would not be the ones investigating.”

Irish Consul General Philip Grant said the families of those killed are arriving in California on Tuesday night, and he urged calm and privacy for them. “There isn’t a family in Ireland not affected,” he said.

The area where the accident took place is traditionally popular with Irish students, whose specialist visas allow them to work legally in the US over the summer.

The Irish foreign minister said he understood the balcony collapse happened as a birthday party was taking place. A number of the dead students’ families had been contacted by the Department of Foreign Affairs, he said.

Irish citizens working on J1 visas in the San Francisco area have been advised to contact their families and friends to let them know that they are safe.

Damage is seen at the scene of a 4th-story apartment building balcony collapse. Photograph: Elijah Nouvelage/Reuters

Dan Sullivan, 21, a student from UCD who had been in the US for less than three weeks and was living on the first floor of the Library Gardens housing complex where the incident occurred, told Inside Bay Area News: “We just heard a bang in the middle of night and shouting ... It’s just a shocker. It’s crazy.”

The Union of Students in Ireland expressed its sympathy for those who died.

Officer Jennifer Coats, of the Berkeley police department, said officers were still investigating at the scene. There were no further details on how the incident occurred.

Berkeley officials said the building code at the time of construction in 2007 required the balcony hold at least 60 pounds per square foot, since raised to 100 pounds. Spokesman Matthai Chakko said officials have not measured the balcony to find out how big it was and how much weight it was built to bear. He said there is no city requirement to post a weight restriction for balconies in apartments.

Ireland’s president, Michael D Higgins, sent a message of condolence from a state visit to Italy. “I have heard with the greatest sadness of the terrible loss of life of young Irish people and the critical injury of others in Berkeley, California, today,” he said.

“My heart goes out to the families and loved ones of all those involved. I have been informed of the consular assistance being provided to all of the families involved and I have asked to be kept informed as further details emerge.”

Debris is seen on the sidewalk below the fourth-story apartment building balcony. Photograph: Elijah Nouvelage/Reuters

Martin McGuinness, Northern Ireland’s deputy first minister, said: “Shocking news of the deaths of several young Irish people in a tragic accident in California. My heart and sympathy goes out to their families.”

The leader of Ireland’s Catholics, Archbishop Eamon Martin, expressed his shock and sadness over the events in Berkeley.

The archbishop said: “This devastating news will be felt by Irish people everywhere, and particularly by those who have family and friends abroad. I pray that the eight injured students will fully recover from this terrible accident.

“The death of a child or young person is the worst news that a parent can receive. At this profoundly painful time I pray for those who have died, and ask also for prayerful support for their grieving families, fellow students and loved ones.”

Many of the students who had been attending the party were past students of St Mary’s College in Rathmines, south Dublin.

University College Dublin president Andrew Deeks sent a message of condolence to the family and friends of those who died.

“We cannot comprehend the desperate shock and grief they are feeling and we are heartbroken at their suffering and loss,” he said.

“Our students, like thousands of others across Ireland, head to the US each summer on J1 visas to enjoy the experience.

“It is heart-breaking to imagine that such a tragedy would strike these wonderful students when their lives are opening up to discover the world.”

• A helpline for Irish families concerned about relatives in Berkeley has been set up at +353 1 418 0200.